Cooling plate comprising a reinforcement element

ABSTRACT

A cooling plate with reinforcing part for furnaces which are provided with a refractory lining. Coolant passages are arranged in the interior of the plate, which is provided with at least one additional cooling segment provided with a cooling passage into which a displacement body is inserted.

[0001] The invention relates to a cooling plate with reinforcing part,for example a reinforced top and/or bottom end, for melting vesselswhich are used to produce pig iron, blast furnaces and shaft furnacesprovided with a refractory lining, in particular including CORE® meltergasifiers, consisting of copper or a low-alloy copper alloy, withcooling passages arranged in its interior, the cooling plate beingmanufactured from a forged or rolled block, the cooling passages beingvertically running blind bores, and tongues and grooves being machinedonto the side which faces the interior of the shaft furnace.

[0002] Cooling plates of this type are usually arranged between thecasing and the refractory lining and are connected to a cooling system.On the side facing the process space, the cooling elements are partiallyprovided with refractory material.

[0003] DE 39 25 280 has disclosed a cooling plate in which the coolingpassages are formed by pipes which are cast into cast iron, and thebottom edge of the plate body is designed as a bearing lug for therefractory brickwork. The bearing lug is likewise connected to thecooling system. Little heat is dispatched from these plates, on accountof the low thermal conductivity of the cast iron and on account of theresistance between the cooling pipes and the plate body, caused by anoxide layer or an air gap.

[0004] After a certain operating time, the loss of the blast furnacerefractory brickwork leads to the inner surface of the cooling platesbeing directly exposed to the temperature of the furnace. Since thefurnace temperature is well above the melting point of cast iron and theinternal heat transfer resistances of the cooling plates lead tounsatisfactory cooling of the hot plate side, accelerated wear to thecast iron plates is inevitable, and the service life is correspondinglylimited.

[0005] Furthermore, plates made from cast copper, in which the coolingpassages are formed either by cast-in tubes or are cast in directly byshaped casting, are known. The microstructure of cast copper is not ashomogenous and dense as that of forged or rolled copper. Consequently,the conduction of heat in cast copper is not as good and the strength islower. In the case of the cast-in pipe, an oxide layer between pipe andcopper block inhibits heat conduction.

[0006] DE 29 07 511 has disclosed a cooling plate which is produced froma forged or rolled block and the cooling passages are vertically runningblind bores which have been formed by deep mechanical drilling. Themicrostructure of the cooling plate is significantly denser and morehomogenous than that of a cast copper plate. Voids, which are oftenfound in cast copper plates, are prevented by the forming process. Thestrength values are higher and the thermal conductivity is more uniformand higher than that of the cast copper plates. Mechanical production ofthe bores means that the desired position in terms of height and lateralposition is accurately maintained, and as a result uniform dissipationof heat is ensured. On the side facing the interior of the furnace, thecooling plate is lined with refractory bricks or with a refractoryramming compound. This reduces the cooling surface area of the plate,and in the event of wear to or loss of the pre-bricked refractorylining, extraction of heat from the furnace is limited. Furthermore, thecooling of the plate needs to be sufficiently intensive to keep thetemperature of the hot side of the plate well below the softening pointof copper.

[0007] DE-A 23 62 974 has disclosed a cooled shaft furnace with a steelcasing, to the inner side of which cooling plates with substantiallyvertical inner tubes are connected; the tubes pass through the steelcasing at the upper and lower ends of the cooling plate. On the sideremote from the steel casing, the cooling plate is provided with aholding protuberance or holding lug, through which another tube, runningin a substantially horizontal plane, runs, with connections leadingthrough the steel casing; at least some of the vertical tubes extendover a considerable part of the vertical dimension.

[0008] FR-A 22 30 730 has disclosed a cooler for the evaporative coolingof a blast furnace, this cooler comprising a plate with a collar, whichis arranged transversely in the vicinity of the end of the plate, andtubes, which are mounted in the plate and in the said collar and inwhich a coolant flows. The inlet and outlet ends of these tubes arearranged at different heights on the opposite side from the collar. Thetube for circulation of the coolant in the collar is configured in sucha way that it is arranged in the collar in such a way that the inlet andoutlet ends are located between the outlet ends of the tubes laid in theplate. The ends of the parts of the circulation tube in the collar,which are located in the interior of this collar, are arranged at anangle of 2 to 4° with respect to the vertical, so that the circulationof the coolant from the inlet end to the outlet end of the tubes rises.

[0009] U.S. Pat. No. 4,071,230 has disclosed cooling elements for ashaft furnace which are secured to the inner side of the furnace shell.The rectangular cooling element is composed of five metallic blockswhich are arranged in a staggered formation above one another and areattached to two vertically running pairs of cooling tubes by means ofsuitable securing elements. The pairs of tubes, with a cooling waterinlet at the bottom and a cooling water inlet at the top, are routedthrough openings in the metallic furnace wall, and the metallic blocksare cooled only on the outer side of the side facing the blast furnacewall.

[0010] EP 0 705 906 A1 has disclosed a cooling plate which ismanufactured from a forged or rolled copper block and in which coolingpassages, which are introduced into the edges as vertical or horizontalblind bores of smaller diameter around the vertically arranged blindbores, are introduced in addition to the vertically running blind bores,in order to cool the edge zones.

[0011] However, a drawback of these rolled or forged copper coolingplates is that the load-bearing capacity of the refractory brickworklining at the top ends of the cooling plate is less than optimal andconsequently the service lives of the refractory ramming compounds orrefractory bricks is also inadequate.

[0012] EP 0 731 108 B1 describes a cooing plate with reinforced andcooled top end. The cooling passages at the reinforcement arecharacterized by their arrangement and/or by the fact that they areproduced by vertical and horizontal blind bores. The cooling medium issupplied and discharged via cooling pipes, which may be included in thecooling system of the shaft furnace.

[0013] A drawback of this variant is the complicated and laboriousproduction of the cooled top end, which often requires the tools to bechanged during production of the blind bores. A plurality of welds orsoldered joints are required to tightly close off these blind bores. Forproduction reasons, these welds and joints are very close to the processchamber and are highly susceptible to failure. It is therefore desirableto minimize the number of these welds and joints. In addition, thecooling passage surface area which is required to achieve the requiredcooling capacity is limited by the geometric design of the attachedrefractory supports.

[0014] Therefore, the object of the invention is to provide a coolingplate with reinforcing part in which cooling and dissipation of heat inthis reinforcing part are likewise uniform and homogenous, so that theretoo, improved cooling of the refractory furnace lining and of thefurnace shell is ensured. In addition, the number of welds requiredshould be reduced to a minimum, and at the same time the available heatexchange surface area should be increased.

[0015] This object is achieved by virtue of the fact that at least oneadditional cooling segment is provided, which is provided with a coolingpassage into which a displacement body is inserted.

[0016] Surprisingly, it has been discovered that it is not necessary toprovide a complicated combination of vertical and horizontal blind boresfor the additional cooling segment. Rather, it has been established thatto achieve the required cooling action it is sufficient for anadditional cooling segment, which may be detachable and into which acooling passage formed by a horizontal bore is introduced, to be fittedto the forged or rolled copper cooling plate, for example in the upperor lower region. To achieve the optimum flow velocity which is requiredfor the heat transfer, a displacement body is additionally inserted intothis bore. The bore is closed off in a sealed manner at the end bywelded or soldered stoppers and is connected to the cooling system viacopper pipe connection pieces.

[0017] As an alternative to a releasable cooling segment, it is alsopossible for a bead for the refractory brickwork to be forged out of thecopper block, in which case the cooling passages are drilled into thisbead in the known way.

[0018] To keep the heat exchange surface area of the cooling passage aslarge as possible, it is advantageous for the diameter of the coolingpassage to be selected to be as large as possible, and at least to belarger than the diameter of the coolant passages of the cooling plate.

[0019] According to a further advantageous embodiment of the coolingplate according to the invention, the displacement body is designed as acavity for routing coolant.

[0020] In an embodiment of this type, the displacement body expedientlyincludes apertures which allow cooling medium to pass out of the coolingpassage into the interior of the displacement body and from the latterback into the cooling passage.

[0021] According to an advantageous embodiment, bores for supplying anddischarging cooling water open out into the cooling passage.

[0022] According to an alternative embodiment, pipe sections forsupplying and discharging cooling water open out into the displacementbody, which is designed as a cavity, in which case the pipe sections arepushed into the bores and are screwed to the displacement body at thelocation where they open out.

[0023] The bores for supplying and discharging cooling water may bedesigned so as to run horizontally or at an angle.

[0024] The invention is explained in more detail on the basis ofdiagrammatic embodiment drawings, in which:

[0025]FIG. 1 shows a horizontal section through the cooling plate withfitted refractory support,

[0026]FIG. 2 shows a cross section through the cooling plate with aforged-out bead,

[0027]FIG. 3 shows a cross section through a releasably attached coolingsegment.

[0028]FIG. 1 shows a horizontal section through the cooling plate 1with, by way of example, five vertically arranged blind bores 3 and withthe cooling passage 5, which is introduced in the cooling segment 4 andis formed by a horizontal bore, and the inserted displacement body 6.

[0029] The cooling water is supplied to the blind bores 3 from below viathe pipe attachments 2, which are connected to the coolant supply lines,and the cooling passage 5 formed by the horizontal bore in the coolingsegment 4 is likewise supplied with cooling water via pipe sections 2.Bores 7 are also arranged in the cooling plate 1, in order to ensure thesupply and removal of cooling water through the wall of the blastfurnace shell via the pipe attachments 2. The cooling circuit of thecooling plate 1 and of the cooling segment 4 may be connected to thecooling system either as separate cooling circuits or as a commoncooling circuit. The displacement body 6 has apertures 11, which allowcooling water to pass out of the cooling passage 5 into the interior ofthe displacement body 6 and back out of the displacement body 6 into thecooling passage 5. The direction of flow of cooling water is indicatedby arrows.

[0030]FIG. 2 shows a section through the cooling plate 1 with thevertically arranged blind bores 3, which are closed off in a known wayat the lower or upper end, as desired, by welds or soldered joints.Cooling water is supplied and discharged via the pipe sections 2. Acooling bead 8, which is forged out of the block and into which thecooling passage 5 formed by the horizontal bore is introduced, is formedin the upper part of the cooling plate 1. Once again, a displacementbody 6 is inserted in the cooling passage 5, in order to ensure theappropriate flow velocity.

[0031] In this case, cooling water is supplied and discharged viainclined bores 7. A pipe section 12, which leads all the way into thedisplacement body 6 and is screwed to the latter, is inserted into eachinclined bore 7. In the embodiment illustrated in FIG. 2, therefore,coolant is supplied into and discharged from the displacement body 6,whereas in the embodiment illustrated in FIG. 1 it is supplied into anddischarged from the cooling passage 5.

[0032] For the introduction of refractory material, either bricks orspraying/ramming compounds, grooves 9, which are in each case delimitedby webs 10, are machined into the cooling plate 1 and into the coolingbead 8 on the side facing the process chamber.

[0033]FIG. 3 shows a releasably fitted cooling segment 4, into which acooling passage 5 formed by a horizontal bore has been introduced. Thedisplacement body 6 is also illustrated. In this case too, thishorizontal bore 5 is connected to the cooling circuit via horizontalbores 7 in the cooling plate 1 and then subsequently via pipeconnections 2 leading through the wall of the shell.

[0034] List of Reference Symbols

[0035]1 Cooling plate

[0036]2 Pipe connections/pipe pieces

[0037]3 Blind bores in 1

[0038]4 Cooling segment

[0039]5 Cooling passage in 4 and in 8

[0040]6 Displacement body

[0041]7 Bores in 1, 4 and 8 for supplying and discharging cooling medium

[0042]8 Reinforced cooling segment/bead

[0043]9 Grooves in 1, 4 and 8

[0044]10 Webs on 1, 4 and 8

[0045]11 Apertures in 6

[0046]12 Pipe section in 7

1.-6. (Canceled)
 7. A cooling plate with a reinforcing part for afurnace having a refractory lining, wherein the cooling plate comprisesa plate having an extent along the lining, the plate having an interior;first coolant passages defined in the interior of the plate, at leastone additional cooling segment of the plate; a second cooling passagedefined in the segment, the second cooling passage running substantiallyhorizontially and parallel to the extent of the cooling plate along therefractory lining; a displacement body inserted into the second coolingpassage, the displacement body including a cavity therethrough forrouting coolant along the cavity.
 8. The cooling plate as claimed inclaim 7, wherein the first coolant passages in the cooling plate havefirst diameters, the second cooling passage in the at least oneadditional cooling segment has a second diameter which is greater thanthe respective first diameters of the first coolant passages in thecooling plate.
 9. The cooling plate as claimed in claim 7, wherein theat least one additional cooling segment is separate from and is securedreleasably to the cooling plate.
 10. The cooling plate as claimed inclaim 7, wherein the at least one additional cooling segment is formedby a bead which is forged out of the cooling plate.
 11. The coolingplate as claimed in claim 7, further comprising bores for supplying anddischarging cooling water, and the bores opening out into the secondcooling passage.
 12. The cooling plate as claimed in claim 11, furthercomprising pipe sections inserted in the bores for supplying anddischarging cooling water, and the pipe sections opening out into thedisplacement body.
 13. The cooling plate as claimed in claim 8 furthercomprising a communication between the cavity in the displacement bodyand the second cooling passage in the at least one additional coolingsegment.
 14. A furnace for metal, comprising an interior furnace wall, arefractory material lining inside the interior wall; a cooling platehaving an extent along the lining having and disposed between theinterior furnace wall and the lining; the plate having an interior;first coolant passages defined in the interior of the plate, at leastone additional cooling segment of the plate; a second cooling passagedefined in the segment, the second cooling passage running substantiallyhorizontially and parallel to the extent of the cooling plate along therefractory lining; a displacement body inserted into the second coolingpassage, the displacement body including a cavity therethrough forrouting coolant along the cavity.